Remove std::move to support copy elision#67
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According to the standard, copy elision is allowed (before C++17) or required (since C++17) in the following situation: In the initialization of an object, when the source object is a nameless temporary and is of the same class type (ignoring cv-qualification) as the target object. When the nameless temporary is the operand of a return statement, this variant of copy elision is known as RVO, "return value optimization". Unfortunately, using std::move() will block this optimization when initializing an object, so it should not be used. Removing it allows the target object to be constructed in-place rather than being copied using the copy constructor.
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According to the standard, copy elision is allowed (before C++17) or required (since C++17) in the following situation:
In the initialization of an object, when the source object is a nameless temporary and is of the same class type (ignoring cv-qualification) as the target object. When the nameless temporary is the operand of a return statement, this variant of copy elision is known as RVO, "return value optimization".
Unfortunately, using std::move() will block this optimization when initializing an object, so it should not be used. Removing it allows the target object to be constructed in-place rather than being copied using the copy constructor.